This invention relates to an image processing apparatus and method. More particularly, the invention relates to an image processing apparatus and method for collectively forming images of at least two colors.
The applicant has proposed an image forming apparatus such as a digital copier (see U.S. Pat. No. 4,538,182) for reading a color original by a photoelectric transducer such as a color CCD, identifying an image area from color information indicative of the original, separating the image area into a red-component image and a black-component image, and forming the red-component image in the color red and the black-component image in the color black. In other words, the proposed image forming apparatus reproduces the image of a color original in two different colors.
Furthermore, the applicant has proposed a technique for forming an image in two or a plurality of colors at high speed. Specifically, the applicant has proposed a so-called collective transfer system in which the formation and development of a latent image in two or a plurality of colors on a single photosensitive drum is repeated, toner images of two or a plurality of colors are carried on the photosensitive drum simultaneously and the toner images are transferred to recording paper together at one time.
In the art described above, however, the fact that two (or a plurality of) images are formed on one photosensitive drum en bloc means that the toner of the image developed first intercepts the laser beam so that a sufficient latent-image potential cannot be obtained in the formation of the latent image developed next. The problem which arises is that the density of the image of this latter color component declines, as a result of which sufficient mixing of the colors cannot be achieved.